Have everyone line up and put one arm up so their elbow is bent and their hand is close to their shoulder palm up, their elbow should be out in front of them and their forearms flat(ish). They will then take a coin and balance it on their elbow and one at a time or all at once they will attempt to swing their hand down fast so the coin leaves their elbow and they catch it in their hand on the way past. Let them practice a couple of times before starting for real. After the start those who catch it move on and those who don't are eliminated. Those moving on now do the same thing with 2 coins, then 3, etc. The winner is the player(s) who make it to the most coins before missing.

Scoring is, as always, completely arbitrary, you can award only the winner or award points on a sliding scale based on elimination. Decide how you wish based on the number of players.

Most people get the hang of it within a couple of attempts, but give them longer if it's not happening. Get the hang of it yourself first so you can demonstrate.